(a)[2]
Explain why the mass of an $\alpha$-particle is smaller than the combined mass of two separate protons and two separate neutrons.
(b)
One possible nuclear reaction is written as $^{4}_{2}\text{He} + ^{14}_{7}\text{N} \rightarrow ^{17}_{8}\text{O} + ^{1}_{1}\text{p}$. The nuclear masses are listed in Fig. 8.1.
(b(i))[2]
Calculate the mass change, in $\text{u}$, for this reaction.
(b(ii))[2]
Calculate the energy, in $\text{J}$, linked to the mass change in (i).
(b(iii))[2]
Suggest and explain why the helium-4 nucleus needs a minimum speed if this reaction is to happen.